1. Field of the Invention
The present invention relates generally to an air purifier and, more particularly, to an air purifier for removing particulates and for sterilizing or killing micro-organisms from ambient air during a plurality of stages.
2. Description of the Related Art
Air contamination by pollen, mold, smoke, dust, pet dander, micro-organisms or any other of a number of known irritants, is a common and long-standing problem. Contact with these contaminants is almost inevitable and often makes breathing uncomfortable for individuals. Moreover, such contaminants may present long-term health risks, particularly for those individuals suffering from allergies, asthma, emphysema and other respiratory related illnesses.
A wide variety of air purifiers are presently available on the market for removing contaminants from ambient air. These systems typically include a fan for circulating air and a mechanical filter disposed in an air path so as to filter or otherwise purify air flowing therethrough. One type of mechanical filter which has gained wide spread acceptance within the industry is a high efficiency particulate air (HEPA) filter which typically entraps particles larger than 0.3 microns in size.
Since many living micro-organisms are smaller than 0.3 microns, they readily pass through such conventional mechanical filters. It is therefore further known to utilize ultraviolet (UV) light produced by ultraviolet lamps to kill micro-organisms, or to sterilize micro-organisms so they will not reproduce.
Ozone may be generated by subjecting air to ultraviolet light. The amount and type of ozone created depends upon the wavelength and intensity of the energy source. While ozone itself has been utilized for the effective sterilization or destruction of micro-organisms, its use is often discouraged due to ozone""s inherent health risks to humans. Therefore, it is important that any radiation source utilized to reduce micro-organisms effectively minimizes the human exposure to ozone.
While ultraviolet light sources have been found effective in reducing the number of micro-organisms in ambient air, humans must be properly shielded to avoid prolonged direct exposure to ultraviolet light rays which may cause skin and eye damage, including blindness. Therefore, in traditional air purifiers, the ultraviolet light source is usually positioned in a location within the housing remote from the air inlet and air outlet, or requires the use of reflecting shields to restrict the transmission of ultraviolet light. As such, many traditional air purifiers employing an ultraviolet light source include structures which render the replacement of the ultraviolet lamp a difficult and time consuming task.
Accordingly, there is a need for an air purifier including multiple stages for effectively cleaning ambient air. Moreover, there is a need for such an air purifier including a filter assembly for effectively removing particulates from the air and an ultraviolet light source for sterilizing or killing micro-organisms. Further, there is a need for such an air purifier which provides a structure for facilitating the efficient and convenient replacement of both the filter assembly and the ultraviolet light source, while also preventing potentially harmful human exposure to ultraviolet light rays.
The air purifier of the present invention includes a housing supporting an air inlet, an air outlet and an air flow passage interconnecting the air inlet and the air outlet. A blower assembly is supported by a dividing wall positioned within the housing and includes a fan driven in rotation by a motor. The blower assembly draws air through the air inlet and then forces the air through the air flow passage from the air inlet to the air outlet. The housing further includes a rear wall and a spacer extending outwardly from the rear wall for maintaining the housing in spaced relation to external objects, such as walls, in order to ensure proper air flow around the air purifier.
A downstream first air filter, or main filter, is disposed within the air flow passage intermediate the air inlet and the blower assembly. A resilient sealing gasket is supported by the main filter for sealingly engaging the dividing wall and thereby preventing air flow from bypassing the main filter. An upstream second air filter, or pre-filter, is removably secured to the main filter and is positioned intermediate the air inlet and the main filter. The main filter preferably comprises a high efficiency particulate air (HEPA) filter adapted for removing particulates of a size 0.3 microns and greater. The pre-filter preferably comprises a carbon mesh filter adapted to remove odors and larger particulates prior to such particulates contacting the main filter.
An ultraviolet light source is disposed downstream from the main filter and the pre-filter, and is positioned within the air flow passage proximate the air outlet. The ultraviolet light source comprises an ultraviolet lamp oriented in a plane substantially perpendicular to the air flow passage to provide maximum ultraviolet light exposure to air passing in proximity thereto.
An outlet grille is supported by the housing proximate the air outlet and is permeable to air and substantially impermeable to ultraviolet light. The outlet grille preferably comprises a louver assembly including a plurality of mutually horizontally spaced and vertically extending blades defining a plurality of convoluted paths or channels for permitting the passage of air from the air flow passage through the air outlet, while substantially preventing the passage of ultraviolet light from the ultraviolet light source through the air outlet. Each blade preferably includes a body having opposing concave and convex surfaces, longitudinally extending side edges and laterally extending end edges. The concave surface of each blade is positioned adjacent the convex surface of an adjacent blade, wherein the side edges of each blade overlap a portion of the body of an adjacent blade.
An outlet safety switch is selectively engagable with the outlet grille. The outlet safety switch is operably connected to the ultraviolet light source and the blower assembly for deactivating both when the outlet grille is not properly positioned relative to the housing. An inlet grille is supported proximate the air inlet and is selectively engagable with an inlet safety switch. The inlet safety switch is likewise operably connected to the ultraviolet light source and the blower assembly for deactivating both when the inlet grille is not properly positioned relative to the housing.
A controller is operably connected to the motor of the blower assembly for controlling the volume of air moving through the air flow passage. An air quality sensor is supported within the housing and includes a sampling chamber, an optical emitter for providing light to the sampling chamber, and an optical receptor communicating with the sampling chamber for detecting light emitted from the optical emitter. The air quality sensor provides an air quality signal to the controller indicative of the air quality within the sampling chamber. The controller adjusts operation of the blower assembly by varying the motor speed in response to the air quality signal.
A cleaning member is removably receivable within the sampling chamber for manually cleaning the optical emitter and the optical receptor. A storage compartment is provided behind the inlet grille for removably storing the cleaning member when it is not in use.
The controller includes a counter, or timer, for determining the cumulative operating time of the air purifier at each of a plurality of motor operating speeds. When each of first predetermined time intervals has elapsed, then the controller provides for a xe2x80x9ccheck pre-filterxe2x80x9d indicator signal. Likewise, when each of second predetermined time intervals, greater than each of the first predetermined time intervals, has elapsed then the controller provides for a xe2x80x9ccheck HEPA filterxe2x80x9d indicator signal.
A filter check gauge is removably positioned proximate the air outlet for providing an indication of air flow volume. The filter check gauge is removably supported proximate the air outlet for providing an indication of air flow volume therethrough, and more particularly, is supported within a recess formed within the outlet grille. The filter check gauge comprises an open-ended transparent cylindrical tube and an indicator slidably received within the cylindrical tube for moving in response to air flow through the check gauge. A storage compartment is formed behind the inlet grille for removably storing the filter check gauge when it is not in use.
A window is provided within the housing and is in visual communication with the ultraviolet light source for providing the user with an indication of the proper functioning of the ultraviolet light source. The window includes a translucent ultraviolet light filtering cover to protect the user from potentially harmful ultraviolet light rays.
Therefor, it is an object of the present invention to provide a self-contained, portable air purifier.
It is a further object of the present invention to provide such an air purifier including filters for removing particulates and an ultraviolet lamp for sterilizing or killing micro-organisms from ambient air during a plurality of stages.
It is a further object of the present invention to provide an air purifier including easily replaceable filters and an ultraviolet lamp.
It is another object of the present invention to provide an air purifier comprising a plurality of filters including a main filter for entrapping relatively small particulates and a pre-filter for filtering relatively large particulates from ambient air and thereby increasing the effective life span of the main filter.
It is a further object of the present invention to provide such an air purifier including an ultraviolet light source for the sterilization or killing of micro-organisms which pass through upstream filters.
It is still yet another object of the present invention to provide an air purifier including an outlet grille permitting the passage of air but substantially preventing the passage of an ultraviolet light.
It is a further object of the present invention to provide an air purifier including a plurality of interlocking safety switches for preventing inadvertent and potentially harmful exposure to ultraviolet light should the inlet grille or the outlet grille not be properly installed within the air purifier.
It is another object of the present invention to provide a window in visual communication with the ultraviolet light source to permit viewing thereof by a user for verifying proper operation.
It is a further object of the present invention to provide an air quality sensor for sensing ambient air quality and for controlling operation of the air purifier in response thereto.
It is another object of the present invention to provide an automatic filter check indicator signal when a predetermined period of time has elapsed.
It is a further object of the present invention to provide a filter check gauge for simply and efficiently determining air flow volume and the need to replace the air filters.
Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.